Earth's core

AFP English

What is at the centre of the Earth? 5,000 kilometres below the surface, the core lies between layers of rock and magma, as this videographic explains. VIDEOGRAPHIC

Transcript

00:00 What is at the center of the Earth?

00:10 5,000 kilometers below the surface, the core lies between layers of rock and magma.

00:16 The core consists of a liquid outer core, primarily made of iron and nickel along with

00:21 other elements.

00:26 The solid inner core is also composed of an alloy of metals with approximately 90% iron

00:32 and 10% nickel.

00:35 The core's heat is instrumental in the formation of magma and large volcanic regions such as

00:40 Hawaii, Iceland, and Reunion Island.

00:44 The core has not always existed.

00:46 It was formed between 3 and 4 billion years after the Earth was created, when the planet

00:51 began to cool and a liquid core began to crystallize at its center.

00:57 The inner core is often called a planet within a planet.

01:01 It floats and moves freely within the liquid envelope of the outer core.

01:07 It's difficult to study how the core works.

01:10 What we do know is based on the analysis of seismic waves caused by earthquakes.

01:16 These waves pass through the center of the planet.

01:20 Scientists do not know for sure whether the core is spinning on itself and if so, in what

01:26 direction and at what speed.

01:29 We do know some of the effects of the core on the planet.

01:32 It creates the Earth's magnetic field caused by the iron in the core moving around.

01:38 This magnetic field helps many animals find their bearings and allows compasses to work.

01:44 [Music]

01:46 [Music fades]

01:48 [Music fades]

01:50 [Music fades]

01:52 [BLANK_AUDIO]

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